The topical use of insulin accelerates the healing of traumatic tympanic membrane perforations.

Objective: In recent years, there has been a tendency to search for regulatory substances that can optimize the healing process of perforated tympanic membranes (TMs). The purpose of this study was to determine the effects of using topical insulin on the healing process of traumatic TMs perforations.

Study Design: Experimental.

Methods: Tympanic membranes of 20 Wistar rats were perforated in two sections, anterior and posterior to the malleus. The rats were divided into two groups: control and insulin. The insulin group was treated with topical regular insulin. The TMs were histologically examined 3, 5, and 7 days after the perforation through a morphometric analysis of the epithelial layer thickness, perforation size, TM cross-sectional area, semiquantitative and qualitative evaluation of the collagen production by polarization microscopy, and immunohistochemical evaluation of epithelial cells and myofibroblasts markers.

Results: Insulin accelerated the healing process of the perforated TMs (P < 0.01); stimulated early thickening of the outer epithelial layer (P < 0.01); contributed to a larger identification of the antipankeratin antibody as epithelial marker (P < 0.05); and increased labeling of smooth muscle anti-alpha-actin antibody (P < 0.05), indicating greater proliferation of myofibroblasts. When the topical insulin was used, it resulted in a greater formation of collagen tissue (P < 0.05), with thicker and better-organized collagen fibers (P < 0.05).

Conclusion: Insulin accelerated the healing process of TMs traumatic perforations.